This invention relates generally to imaging methods and apparatus, and more particularly, to methods and apparatus that provide non-scanner dependent patient specific data.
Patient characteristics such as, for example, but not limited to, weight, height, girth, diameter, body mass index, gender, age etc. can be used by physicians to attempt to determine the probability of a specific disease, to help establish the proper operating parameters for a medical procedure such as, for example not limited to, the obtaining of a diagnostic image and/or to help in the interpretation of diagnostic images or other diagnostic information or data. Such characterizations may be only loosely related or indirectly represent factors that are significant to the problem. For example, the patient's weight might be used to determine the tube current for a CT or x-ray procedure even though the patient's attenuation derived from a scout scan provides a more accurate deterministic function for the determination of the proper tube current (auto exposure control). Similarly, with PET/CT it is more important to note the density and size of the patient (rather than the weight) in determining the activity of the agents to be used and the imaging time. Knowledge of the regional density of the patient can provide valuable information to the physician.
It is contemplated that patient x-ray attenuation information can be employed as a patient factor that can be used to improve the outcome for a wide variety of medical diagnostic and treatment problems. Therefore described below are methods and apparatus that provide for scanner independent patient specific x-ray attenuation data. As used herein scanner independent means the same as non-scanner dependent.